The smoking ban has resulted in 1,900 fewer asthma-related emergency hospital admissions a year.
That's the conclusion of a new study which shows the ban on smoking in public places, implemented in England in July 2007, has been linked with an annual fall of nearly 5% in adult admissions.
University of Bath researchers analysed the number of emergency admissions during the three years after the law came into force.
They examined the 502,000 hospital emergency cases for asthma among adults aged 16 or more in England between April 1997 and December 2010.
The data found that the number fell by 4.9% among adults for each of the first three years following the introduction of the smoking ban.
Researchers stress that this took into account seasonal temperatures, variations in population size, and long term trends in the prevalence of asthma.
The fall was seen to be constant across England.
Smoking laws introduced elsewhere have been associated with up to 40% reductions in the number of emergency asthma admissions.
The authors said that although the 5% drop is lower than decreases noted overseas, this might be because many workplaces in England had already established smoke-free policies before the nationwide ban came in.
The prevalence of asthma in England is one of the highest in the world, hitting almost 5.9% of the population.
The research is being published in the journal Thorax .
Copyright Press Association 2013